What is preferable; WMT or WTM horizontal driver arrangement?
I am buying components for a floor to ceiling open baffle line array. The array consists of 24x 12cm vintage alnico drivers supported by 8x 15" woofers and 36 dipole amt's. All first order crossovers at 300Hz and 3600Hz (not set in stone....start of voicing)
Before I start cutting wood I need to decide between WMT or WTM.
And after building I need to decide to place the speakers with woofers on the inside or outside.
Instinctively I would go with WMT TMW but I see many examples of people going for WTM. Anyone can point me to some pro's and con's of different arrangements?
Thanks!
I am buying components for a floor to ceiling open baffle line array. The array consists of 24x 12cm vintage alnico drivers supported by 8x 15" woofers and 36 dipole amt's. All first order crossovers at 300Hz and 3600Hz (not set in stone....start of voicing)
Before I start cutting wood I need to decide between WMT or WTM.
And after building I need to decide to place the speakers with woofers on the inside or outside.
Instinctively I would go with WMT TMW but I see many examples of people going for WTM. Anyone can point me to some pro's and con's of different arrangements?
Thanks!
Keep the woofer panel stand alone…..there’s no horizontal distance issue to concern yourself with and now you’re allowed the flexibility of adjustment with co location. You’ll also keep all of that resonant energy from infecting your very delicate AMT membranes.
As for the mids and high panels…..mirror images of course…..that allows you an alternate placement of either inside or outside tweeters during your voicing stage of the build and flexibility in different rooms should you chose….or move to another home.
12cm is a pretty small midwoofer but at 3.6k……make sure they’re as close as possible to your AMTs and to eachother on the horizontal plane. Sounds like you have them already?……..hopefully they have truncated frames or you’ll find yourself lowering that XO point a bit…..which isn’t a bad thing………36 AMTs can play pretty darn low in frequency…….2k wouldn’t scare me in the least………now if you used ribbons?……..
As for the mids and high panels…..mirror images of course…..that allows you an alternate placement of either inside or outside tweeters during your voicing stage of the build and flexibility in different rooms should you chose….or move to another home.
12cm is a pretty small midwoofer but at 3.6k……make sure they’re as close as possible to your AMTs and to eachother on the horizontal plane. Sounds like you have them already?……..hopefully they have truncated frames or you’ll find yourself lowering that XO point a bit…..which isn’t a bad thing………36 AMTs can play pretty darn low in frequency…….2k wouldn’t scare me in the least………now if you used ribbons?……..
Yes. I fell in love with this little 12cm vintage Alnico driver made by Sharp. I bought an online sellers entire new old stock of 200 drivers. I did some projects with the peerless tc9fd before but this driver sounds more dynamic, alive and detailed.
But it is only rated at 2w so the woofer crossover is quite high at around 300Hz to relieve them of most of their bass duties. So at that high of a crossover I think separating the woofer collum wouldn't sound good.
Once relieved of having to play low frequencies these 2watt drivers can play astonishingly loud.
WMT - TMW is what I would pick too. You can play with it somewhat but based on our general perception of stereo through the frequency range I kind of expect the tweeters on the inside would work best. Based on old papers like the mid/side S-curve: https://sengpielaudio.com/FrequenzabhHoerereignisrichtung.pdf
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Since there are 8x 15" woofers per side I think the vibration will be quite limited. It is the equivalent of a 42" driver....imagine the sound pressure with just one mm of excursion.
Why?........at 300hz the 1/2 wavelength is at 22".....worst case. So co locating the woofer column and using 15" woofers, your center to center distance is well within acceptable distance.
You build this OB with 15" woofers on the same baffle with AMT's?.....THAT'S not going to sound good......AMT elements are very light in nature while the magnets are strong......and dense.....which means resonance.
Not to mention think how much easier said system would be to build and transport........and keep in mind the flexibility.
I thought about that.....slot loaded OB for the woofers. But then there will be a large box like structure right next to the high frequency drivers....almost like a built in sidewall. I considered making the line source shorter and putting SLOB's at both ends..... But I like to keep it close to a true line source.Maybe he should use a vibration canceling side woofer arrangement.
Wesayso, do you agree with mayhem13 that it is a bad idea to have the woofers and AMT's on the same baffle?